| Autor: |
Watkins, Justin M., Ross-Elliott, Timothy J., Shan, Xiaoyi, Lou, Fei, Dreyer, Bernd, Tunc-Ozdemir, Meral, Jia, Haiyan, Yang, Jing, Oliveira, Celio Cabral, Wu, Luguang, Trusov, Yuri, Schwochert, Timothy D., Krysan, Patrick, Jones, Alan M. |
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| Zdroj: |
Science Signaling; 8/10/2021, Vol. 14 Issue 695, p1-16, 16p |
| Abstrakt: |
The bias is in the system: In Arabidopsis, the nutrient glucose and the bacterial peptide flg22 both induce the internalization of the RGS protein AtRGS1 but trigger different transcriptional responses. Watkins et al. found that the distinct changes in cellular responses were mediated by segregated signaling pathways. Glucose and flg22 induced the internalization of AtRGS1 through different forms of endocytosis and required different phosphorylation events, endocytic adaptor proteins, and G protein subunits. Because of these systemic biases, only flg22 triggered MAPK and Ca2+ signaling before changes in gene expression. Thus, AtRGS1 links the appropriate signaling outputs to the corresponding signaling inputs through differences in the architecture of the signaling pathways that originate at the plasma membrane. In animals, endocytosis of a seven-transmembrane GPCR is mediated by arrestins to propagate or arrest cytoplasmic G protein–mediated signaling, depending on the bias of the receptor or ligand, which determines how much one transduction pathway is used compared to another. In Arabidopsis thaliana, GPCRs are not required for G protein–coupled signaling because the heterotrimeric G protein complex spontaneously exchanges nucleotide. Instead, the seven-transmembrane protein AtRGS1 modulates G protein signaling through ligand-dependent endocytosis, which initiates derepression of signaling without the involvement of canonical arrestins. Here, we found that endocytosis of AtRGS1 initiated from two separate pools of plasma membrane: sterol-dependent domains and a clathrin-accessible neighborhood, each with a select set of discriminators, activators, and candidate arrestin-like adaptors. Ligand identity (either the pathogen-associated molecular pattern flg22 or the sugar glucose) determined the origin of AtRGS1 endocytosis. Different trafficking origins and trajectories led to different cellular outcomes. Thus, in this system, compartmentation with its associated signalosome architecture drives biased signaling. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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